1. Field of the Invention
This invention relates to the mixing and gasification of a liquid in a vessel.
2. Description of the Prior Art
Liquid suspensions are conventionally prepared in microbial, chemical, and manufacturing applications by combining a variety of ingredients into narrow-necked vessels such as flasks or carboys. Mixing is required initially to distribute and dissolve the ingredients when preparing a suspension. After initial preparation, mixing is usually required on a continuous basis to maintain the suspension in a homogeneous state.
Bacteria and algae are routinely grown in nutrient solutions in flasks or carboys in microbiological applications. The liquid media include a wide variety of ingredients. Aeration or gasification is often required for optimal growth of the culture. Continuous mixing of the liquid in the vessel is essential to ensure homogeneity of the media, circulation of nutrients, prevention of settling, infusion of gases and, in the case of photosynthetic cultures, equalizing cell access to illumination.
The need for mixing and aeration in a microbial culture growing in a liquid has been conventionally addressed by attaching an aeration tube to a low pressure pump and immersing the tube into the vessel.
Prior art systems teach a bubbling method for liquids in vessels with microalgal culture. This conventional method of inserting an aeration tube to achieve mixing produces air bubbles that rise haphazardly and unevenly in the culture vessel, i.e., the air bubbles do not circulate the liquid media in a consistent pattern. The lack of consistency in mixing inhibits growth of the culture due to non-uniformity of cell access to nutrition, aeration, infused gases, and illumination, i.e., the absence of sustained efficient mixing and continuous patterned circulation within the vessel prevents the attainment of optimal results.
Since ongoing mixing is essential for optimal growth of many microbial cultures, mechanical shakers and stirrers are often employed in lieu of bubblers. These devices are expensive, energy-intensive, and do not incorporate the infusion of gases. Accordingly, they often fail to circulate the deeper levels of the liquid media and otherwise fail to provide energy-efficient, inexpensive optimal circulation.
In areas of applied and industrial chemistry, absorption of gases such as oxygen, chlorine, sulfur, or hydrogen into a liquid often represents a critical step in producing a chemical reaction. Bubble columns, vortex reactors, venturi scrubbers, trickle bed reactors, spray columns, and the like may be used to achieve gas-liquid reactions in a solution. Each of these options represents a substantial capital investment.
There is a need, therefore, for a mixing apparatus that consumes less energy than conventional devices, is less expensive to manufacture, that incorporates the infusion of gases into its functionality, and that creates a flow pattern that continually lifts the bottom layer of the culture to the top of the vessel.
There is also a need for a mixing apparatus having no mechanical moving parts of the type found in mechanical mixing devices.
The needed device would have utility in manufacturing and food processing, such as fermentation, carbonation, hydrogenation, steam injection, and pH control.
However, in view of the prior art taken as a whole at the time the present invention was made, it was not obvious to those of ordinary skill how the identified needs could be fulfilled.